Christian experientialism is gaining in popularity - it can be seen in most modern conservative Christian fellowships. Christians want to experience closeness to God and they may calm their minds, and let go of the busyness of day-to-day life in order to allow God to fill them with His Presence. Some may speak in 'heavenly tongues', or receive other 'spiritual gifts'. Others may receive guidance directly from God, or deep insight into spiritual realities, whilst others may be 'caught up' to God in Transcendent Bliss in Divine Love. Pentecostal and Charismatic Christians consider that these spiritual experiences form the essence of New Testament Christian living, and lead to holiness, victory over sin and conformity to God's will. There is a long tradition of Christian experientialism within Judeo-Christian thought and practice, where Christian Mystics in particular seek to cultivate a sense of the Presence of God, teaching the steps that Christians face on their way to closer fellowship with God. This study explores Christian experientialism from a Biblical perspective over two volumes. Volume one explores what it means to have an experiential sense of God, and presents an outline of the history of mysticism within the church. Principles of Scripture interpretation are considered, particularly in relation to allegorical and metaphorical interpretations of texts. The nature of spiritual authority is considered, as is the 'Baptism of the Spirit', visions, trances, appearances and the 'opening of the mind'. Finally the theme of 'spiritual gifts' is explored together with question of whether God still continues to give them in the present day.